First make sure you have the pivot table toolbar appearing.

Then on the toolbar select
Pivot-table..formulas --calculated field
and enter the exact same formula by clicking on the fields (sales,costs )
on the formula bar

Hit OK and change the format to %

This will be the gross margin

"Martin" wrote:

Hello everyone

I am trying to calculate the Gross Margin ( (Sales-cost)/Sales ) within a
pivot table so the total calculate the gross margin of the total sales and
Total cost. (The Average DO NOT work because of this formula.)

Please Help